/*

    File:       ComponentVideoPayload.c

    Contains:   Definition of ComponentVideoPayload operations

    Copyright:  © 1997-1999 by Apple Computer, Inc., all rights reserved.

*/

#include "ComponentVideoPayload.h"

#include <Endian.h>

#include <string.h>

enum    /* fixed header fields */

{

    __kDescriptionFlagWord      = 0,

    __kDescriptionFlagPosition  = 31,

    __kDescriptionFlagSize      = 1,

    __kDescriptionSeedWord      = 0,

    __kDescriptionSeedPosition  = 0,

    __kDescriptionSeedSize      = 31,

    __kOffsetWord               = 1,

    __kOffsetPosition           = 4,

    __kOffsetSize               = 28

};

enum    /* payload description fields */

{

    __kWidthWord                = 0,

    __kWidthPosition            = 15,

    __kWidthSize                = 15,

    __kHeightWord               = 0,

    __kHeightPosition           = 0,

    __kHeightSize               = 15

};

static

UInt32

__SetBitField(

    UInt32 *    inStorageUnit,

    UInt32      inPosition,

    UInt32      inSize,

    UInt32      inValue )

{

    UInt32  theMask = ( ( 1UL << inSize ) - 1 ) << inPosition;

    *inStorageUnit =

        EndianU32_NtoB(

            ( EndianU32_BtoN( *inStorageUnit ) & ( ~theMask ) ) |

            ( theMask & ( inValue << inPosition ) ) );

    return( inValue & ( theMask >> inPosition ) );

}

static

UInt32

__BitField(

    const UInt32 *  inStorageUnit,

    UInt32          inPosition,

    UInt32          inSize )

{

    return( ( EndianU32_BtoN( *inStorageUnit ) >> inPosition ) & ( ( 1UL << inSize ) - 1 ) );

}

UInt32

ComponentVideoPayloadDescriptionSeedLimit(

    void )

{

    return( ( 1UL << __kDescriptionSeedSize ) - 1 );

}

ComponentVideoPayload *

ComponentVideoPayloadInitialize(

    ComponentVideoPayload *     inPayload,

    UInt16                      inWidth,

    UInt16                      inHeight )

{

    memset( inPayload, 0, sizeof( *inPayload ) );

    ComponentVideoPayloadSetDescription( inPayload, inWidth, inHeight );

    return( inPayload );

}

UInt32

ComponentVideoPayloadSetOffset(

    ComponentVideoPayload *     inPayload,

    UInt32                      inOffset )

{

    UInt32  theResult;

    theResult =

        __SetBitField(

            &inPayload->itsFixedHeader[ __kOffsetWord ], __kOffsetPosition, __kOffsetSize,

            inOffset >> 2 ) << 2;

    return( theResult );

}

UInt32

ComponentVideoPayloadSetDescription(

    ComponentVideoPayload *     inPayload,

    UInt16                      inWidth,

    UInt16                      inHeight )

{

    UInt32  theResult;

    theResult = ComponentVideoPayloadDescriptionSeed( inPayload );

    if( inWidth  &&  inHeight )

    {

        if(

            inWidth != ComponentVideoPayloadWidth( inPayload )  ||

            inHeight != ComponentVideoPayloadHeight( inPayload ) )

        {

            theResult =

                __SetBitField(

                    &inPayload->itsFixedHeader[ __kDescriptionSeedWord ],

                    __kDescriptionSeedPosition, __kDescriptionSeedSize, theResult + 1 );

            __SetBitField(

                &inPayload->itsDescription[ __kWidthWord ], __kWidthPosition, __kWidthSize,

                inWidth );

            __SetBitField(

                &inPayload->itsDescription[ __kHeightWord ], __kHeightPosition,

                __kHeightSize, inHeight );

        }

    }

    __SetBitField(

        &inPayload->itsFixedHeader[ __kDescriptionFlagWord ], __kDescriptionFlagPosition,

        __kDescriptionFlagSize, inWidth  &&  inHeight );

    return( theResult );

}

UInt32

ComponentVideoPayloadCopyDescription(

    ComponentVideoPayload *         inTargetPayload,

    const ComponentVideoPayload *   inSourcePayload )

{

    UInt32  theResult;

    __SetBitField(

        &inTargetPayload->itsFixedHeader[ __kDescriptionFlagWord ],

        __kDescriptionFlagPosition, __kDescriptionFlagSize,

        ComponentVideoPayloadHasDescription( inSourcePayload ) );

    theResult =

        __SetBitField(

            &inTargetPayload->itsFixedHeader[ __kDescriptionSeedWord ],

            __kDescriptionSeedPosition, __kDescriptionSeedSize,

            ComponentVideoPayloadDescriptionSeed( inSourcePayload ) );

    __SetBitField(

        &inTargetPayload->itsDescription[ __kWidthWord ], __kWidthPosition, __kWidthSize,

        ComponentVideoPayloadWidth( inSourcePayload ) );

    __SetBitField(

        &inTargetPayload->itsDescription[ __kHeightWord ], __kHeightPosition, __kHeightSize,

        ComponentVideoPayloadHeight( inSourcePayload ) );

    return( theResult );

}

Boolean

ComponentVideoPayloadHasDescription(

    const ComponentVideoPayload *   inPayload )

{

    return(

        __BitField(

            &inPayload->itsFixedHeader[ __kDescriptionFlagWord ],

            __kDescriptionFlagPosition, __kDescriptionFlagSize ) );

}

UInt32

ComponentVideoPayloadDescriptionSeed(

    const ComponentVideoPayload *   inPayload )

{

    return(

        __BitField(

            &inPayload->itsFixedHeader[ __kDescriptionSeedWord ],

            __kDescriptionSeedPosition, __kDescriptionSeedSize ) );

}

UInt32

ComponentVideoPayloadOffset(

    const ComponentVideoPayload *   inPayload )

{

    return(

        __BitField(

            &inPayload->itsFixedHeader[ __kOffsetWord ], __kOffsetPosition,

            __kOffsetSize ) << 2 );

}

UInt16

ComponentVideoPayloadWidth(

    const ComponentVideoPayload *   inPayload )

{

    return(

        __BitField(

            &inPayload->itsDescription[ __kWidthWord ], __kWidthPosition, __kWidthSize ) );

}

UInt16

ComponentVideoPayloadHeight(

    const ComponentVideoPayload *   inPayload )

{

    return(

        __BitField(

            &inPayload->itsDescription[ __kHeightWord ], __kHeightPosition,

            __kHeightSize ) );

}